From fb8965942c99da688ba6737c3aeee1c41f57d11f Mon Sep 17 00:00:00 2001
From: wheremyfoodat <44909372+wheremyfoodat@users.noreply.github.com>
Date: Thu, 3 Aug 2023 11:32:51 +0300
Subject: [PATCH] [Kernel] Implement APIs for detecting Citra & Panda

---
 include/kernel/kernel.hpp  |  1 +
 src/core/kernel/kernel.cpp | 77 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/include/kernel/kernel.hpp b/include/kernel/kernel.hpp
index 99687ee1..06f5dceb 100644
--- a/include/kernel/kernel.hpp
+++ b/include/kernel/kernel.hpp
@@ -128,6 +128,7 @@ private:
 	void getResourceLimit();
 	void getResourceLimitLimitValues();
 	void getResourceLimitCurrentValues();
+	void getSystemInfo();
 	void getSystemTick();
 	void getThreadID();
 	void getThreadPriority();
diff --git a/src/core/kernel/kernel.cpp b/src/core/kernel/kernel.cpp
index c48c8f18..e7b34923 100644
--- a/src/core/kernel/kernel.cpp
+++ b/src/core/kernel/kernel.cpp
@@ -50,6 +50,7 @@ void Kernel::serviceSVC(u32 svc) {
 		case 0x25: waitSynchronizationN(); break;
 		case 0x27: duplicateHandle(); break;
 		case 0x28: getSystemTick(); break;
+		case 0x2A: getSystemInfo(); break;
 		case 0x2B: getProcessInfo(); break;
 		case 0x2D: connectToPort(); break;
 		case 0x32: sendSyncRequest(); break;
@@ -253,6 +254,82 @@ void Kernel::duplicateHandle() {
 	}
 }
 
+namespace SystemInfoType {
+	enum : u32 {
+		// Gets information related to Citra (We don't implement this, we just report this emulator is not Citra)
+		CitraInformation = 0x20000,
+		// Gets information related to this emulator
+		PandaInformation = 0x20001,
+	};
+};
+
+namespace CitraInfoType {
+	enum : u32 {
+		IsCitra = 0,
+		BuildName = 10,     // (ie: Nightly, Canary).
+		BuildVersion = 11,  // Build version.
+		BuildDate1 = 20,    // Build date first 7 characters.
+		BuildDate2 = 21,    // Build date next 7 characters.
+		BuildDate3 = 22,    // Build date next 7 characters.
+		BuildDate4 = 23,    // Build date last 7 characters.
+		BuildBranch1 = 30,  // Git branch first 7 characters.
+		BuildBranch2 = 31,  // Git branch last 7 characters.
+		BuildDesc1 = 40,    // Git description (commit) first 7 characters.
+		BuildDesc2 = 41,    // Git description (commit) last 7 characters.
+	};
+}
+
+namespace PandaInfoType {
+	enum : u32 {
+		IsPanda = 0,
+	};
+}
+
+void Kernel::getSystemInfo() {
+	const u32 infoType = regs[1];
+	const u32 subtype = regs[2];
+	log("GetSystemInfo (type = %X, subtype = %X)\n", infoType, subtype);
+
+	regs[0] = Result::Success;
+	switch (infoType) {
+		case SystemInfoType::CitraInformation: {
+			switch (subtype) {
+				case CitraInfoType::IsCitra:
+					// Report that we're not Citra
+					regs[1] = 0;
+					regs[2] = 0;
+					break;
+
+				default:
+					Helpers::warn("GetSystemInfo: Unknown CitraInformation subtype %x\n", subtype);
+					regs[0] = Result::FailurePlaceholder;
+					break;
+			}
+
+			break;
+		}
+
+		case SystemInfoType::PandaInformation: {
+			switch (subtype) {
+				case PandaInfoType::IsPanda:
+					// This is indeed us, set output to 1
+					regs[1] = 1;
+					regs[2] = 0;
+					break;
+
+				default: 
+					Helpers::warn("GetSystemInfo: Unknown PandaInformation subtype %x\n", subtype);
+					regs[0] = Result::FailurePlaceholder;
+					break;
+			}
+
+			break;
+		}
+
+		default: Helpers::panic("GetSystemInfo: Unknown system info type: %x (subtype: %x)\n", infoType, subtype); break;
+	}
+}
+
 std::string Kernel::getProcessName(u32 pid) {
 	if (pid == KernelHandles::CurrentProcess) {
 		return "current";